The invention relates to a spindle motor with a sealing, flexible support film.
It is extremely important to construct spindle motors so that the interior of the spindle is sealed tight against the external environment, ie so that no air can be admitted into the interior of the spindle motor from the connection side of the spindle motor.
In this case the critical point on the spindle motor is the connection side which as a rule consists of connecting pins and establishes the electrical connection to the connecting wires.
The feed-through of such plugs through the base plate of the spindle motor raises serious difficulties because this feed-through channel must be sealed off in a suitable manner. In doing this it is known to fill the aperture with an (elastic) adhesive, that is to say the connecting plug together with its plug housing is bonded into place in the opening by means of a preferably elastic adhesive. This type of connection, however, suffers from the serious disadvantage that the adhesive used tends to give off foreign gases which get into the protected interior of the spindle motor and may eventually deposit on the storage disks rotating there.
The underlying aim of the invention is, therefore, to extend the sealing of a spindle motor in the region of the connecting pins in such a way that the seal is reliably tight and any evolution of foreign gases is most effectively prevented.
In order to solve the task set the invention is characterised by a support film together with at least one soldering land for soldering the connecting pin and effecting the sealing of the opening in the base plate of the motor.
A characteristic of one embodiment of the invention is that the connecting plug in question is inserted in an opening of the base plate, that connecting pins pass through the insulating body of the connecting plug and terminate in a support film. The connecting pins are soldered by soldering lands on the support film and furthermore the support film seals off the opening in the base plate in that it is arranged on a level, self-contained surface surrounding the opening and is bonded over its entire surface to the latter.
With the stated technical precept the substantial advantage emerges that according to the invention a support film is now used to seal the opening in which support film there is at least one soldering land for soldering the connecting pin or pins on the support film.
Due to the property of the liquid solder to wet the connecting pin and the surface of the soldering land oriented at right angles to it over their entire surfaces in a way which completely envelopes them the melt in the soldering process forms a surface in the shape of a funnel, trumpet or cone which is retained on solidification and reliably and permanently seals the passage of the connecting pin through the support film.
A further characteristic of an embodiment of the invention is that the support film has at least one adhesive layer with which the support film is bonded in sealing manner on the assigned surface of the region surrounding the opening in the base plate.
An important point in this case is that this adhesive layer, which is preferably a PSA layer, does not give off any foreign gases. The abbreviation xe2x80x9cPSAxe2x80x9d stands for a pressure-sensitive adhesive which under an appropriate contact pressure develops an adhesive force and hence brings about surface bonding of the support film to the base plate in the region surrounding the opening for the connecting plug in the base plate.
Thus, this opening is reliably sealed due on the one hand to the fact that the bore in the support film through which the connecting pin passes is sealed in gas-tight manner by the soldering and on the other hand due to the fact that the support film itself is bonded over its entire area to the corresponding surface of the base plate by means of the previously described adhesive layer in the region surrounding the opening.
Instead of the adhesive layer based on a pressure-sensitive adhesive mentioned here it is also possible to use other bonding methods such as, for example, a double adhesive layer which is connected as a separate part in the manner of a double adhesive tape to the support film.
It is also possible to use contact adhesives but these have to be selected with a view to the requirement that they do not give off foreign gases under the corresponding ambient conditions.
In doing this it is desirable that the support film is arranged in the region of the opening in the base plate in such a way that the free surface of the adhesive layer which may give off foreign gases is arranged to be as far away as possible from this opening in order to minimise the amount of such foreign gases which penetrate into the interior or to prevent this completely.
To this end it is provided for example in a first embodiment that in the case of an inwardly arranged support film the adhesive layer is arranged underneath the support film, ie facing towards the base plate, in order to prevent foreign gases from the adhesive layer on the support layer diffusing into the interior.
Once the housing of the connecting plug also comes to rest in the form of a limit stop on assigned stop surfaces in the base plate in the region of the opening it can be provided in a development of the connection that these limit stop surfaces between the plug housing and the assigned surfaces of the base plate are also additionally bonded and/or sealed.
In all embodiments it is a matter of indifference whether the support film is arranged on the inward surface of the base plate inside the opening or whether the support film is stuck on outside the base plate on the assigned outward facing surface of the base plate.
Accordingly, through the invention all embodiments are claimed, ie both a support film which glues off the opening through the base plate from the inside as well as a support film which closes this opening from the outside.
Of course such sealing support films can also be used from both sides.
In all embodiments the support film assumes a double function since on the one hand the connecting pin passing through the support film is soldered to the associated soldering land, this soldering point sealing the passage hole for the connecting pin by means of the solder used, and on the other hand seals the support film for its part towards the outside by bonding with the corresponding surface of the opening in the base plate.
The subject matter of the present invention emerges not only from the subject matter of the individual patent claims but also from the combination of the single patent claims with one another.
All of the details and characteristics disclosed in the documents including the summary, in particular the spatial construction illustrated in the drawings, are claimed as elements substantiating invention in so far as singly or in combination they are novel with respect to the state of the art.
The invention is explained in more detail below with reference to drawings illustrating just one method of construction. In doing this further characteristics and advantages of the invention substantiating invention emerge from the drawings and their description.